TAIM WESER, the leading Spanish company in bulk materials handling, lifting, waste treatment and renewable energy, is also a pioneer in developing biomass gasification technology in the country. Several years of research and testing in this field, in collaboration with the University of Zaragoza and the Institute for Diversification and Saving of Energy (IDAE, in its Spanish acronym) have given rise to an innovative gasification technology, as well as its application in the design and construction of a high energy efficiency biomass plant that is performing at full capacity in the facilities located in Cartuja Baja, Zaragoza.
With this prototype plant, the TAIM WESER renewable energy division opens a new line of business for the company, offering clients a comprehensive energy solution through a biomass plant that is virtually made to order and which can be adapted to a variety of different needs.
In addition to the electrical energy produced through gasification, the plant also recovers and takes advantage of the thermal energy produced in the process, for heating, cooling, drying or other purposes. TAIM WESER has the capacity to respond to the needs of its clients, implementing different applications to maximize the use of this recoverable thermal energy.
The plant also features a modular design and occupies very little space, so that it can be installed right where biomass waste from industrial or agroforestry processes is produced, in order to convert it into renewable energy.
A sophisticated Technology Solution
The plant is based on a Downdraft type gasifier with a fluidized bed and co-current downward flow. It has nominal electric power of 650-750 Kwe, recoverable thermal power of 1200-1400 Kwt and uses 10% for self-consumption.
One of the many advantages afforded by the design of the TAIM WESER invention is the low tar content of the producedgas. The gasifier consists of a cylindrical metallic structure internally lined with heat-resistant refractory material that can withstand temperatures of 1000/1200ºC. The high temperatures make it possible to use thermal cracking to remove the tar produced during gasification, making the subsequent gas conditioning stage much less complicated and giving rise to a very simple, low-maintenance plant and, ultimately, a considerably more feasible project in terms of economic considerations.
The plant is controlled by a system designed and programmed by TAIM WESER, which monitors all the parameters necessary for carrying out a complete and thorough control of its operation. It relies on PLC and fieldbus to transmit system variables between PLC and sensors/actuators, and is powered by SCADA type software that makes it possible to control and supervise the entire plant from a central computer and, in addition, enables remote control from another computer.
A Description of the whole Process
The biomass is unloaded in a covered reception area where it is conditioned by means of crushing and drying processes. In this respect, the characteristics of the gasifier permit a great deal of flexibility with respect to the composition of the biomass, as well as a wide selection of grain sizes, ranging from approximately 0.2 to 10 cm, that greatly facilitates the conditioning process, with the ensuing savings in cost.
Once in the gasifier, the biomass is subjected to a thermochemical combustion process under oxygen deficit conditions, leading to the production of gas and the degradation of the biomass, which is converted to ash. The resulting synthesis gas, after a cleaning and conditioning process, is then oxidized in a cogeneration unit (internal combustion motor) and, in this manner, electrical energy is produced.
In turn, the thermal energy generated in the gasification process and that produced by the cogenerator unit (motor) can be used both for drying the biomass, if it arrives at the plant with moisture levels that exceed optimum performance levels (10/15%), as well as to produce a form of useful heat: industrial processes, heating warehouses, central heating systems in public and residential buildings, drying processes (alfalfa, paint ovens, etc.), among other applications.
Technical specifications of the gasification plant
Type of fuel: Wood chips
Moisture content: 10-15%
Size: 0.2 – 10 cm
Biomass consumption: 650-750 kg/h
P.C.I. gas synthesis: 1.32-1.55 kWh/Nm3
Volume of gas in motor: 1170-1470 Nm3/h
Ash: 15-35 Kg/h
Electrical power: 650-750 kWe
Recoverable thermal power; 1200-1400 kWt
Self-consumption (not including biomass preparation): 10%
Operating hours; 7000 hours/year
Number of operators: 1 per shift